Data presented is part of abstract and poster titled "Entangling Superconducting Qubits over Optical Fiber ? Towards Optimization and Implementation" presented at "IEEE International Conference on Quantum Computing and Engineering - QCE22". Data includes a demonstration of squeezed light generation as the twin beam difference current relative to shot noise and a numerical simulation of the performance of 4 quantum network topologies.

Data for "Quantum gate teleportation between separated qubits in a trapped-ion processor"

These data files contain the data for the measured transition frequencies shown in Table I and the traces in Figure 3 of the publication "Frequency-comb spectroscopy on pure quantum states of a single molecular ion," accessible at https://arxiv.org/abs/1911.12808. In this publication we use generally applicable quantum-logic techniques to prepare a trapped molecular ion in a single quantum state, drive terahertz rotational transitions with an optical frequency comb, and read out the molecular state non-destructively, leaving the molecule ready for further manipulation. One file contains data For Table 1. In the measurement of rotational transition frequencies, the intensities of the comb beams are varied to characterize the effect of AC Stark shift, while the intensity ratio between the sigma and pi polarized beams are kept at close to 2. The average intensity of the sigma-polarized comb beam is quantified by measuring the resultant Stark shift, fSS_sigma, on the 729 nm transition of the Ca+ ion, with the Ca+ ion where the CaH+ ion would be during rotational spectroscopy experiments. The other file contains data for Figure 3, (a) Spectra for the J = 4 to 2 transition: 40CaH+ is prepared in J = 2, followed by a pulse train from the comb Raman beams probing the J = 2 to J = 4 transition. After the probe pulse train, projective measurements of both initial and final states are performed and the state occupation probability is determined. The probe time is ~1.6 ms. The frequency shows the offset of the Raman difference frequency from the resonant value. (b) Rabi flopping on the J = 4 to J = 2 transition: Starting in J = 4, with the comb Raman pulse detuning set to resonance, the state of the 40CaH+ ion is driven coherently to J = 2 by a pulse train of variable duration from the comb Raman beams. The center wavelength of the frequency comb was ~800 nm for these spectra and Rabi flopping traces. The error bars stand for ±1 standard deviation.

Data for "Direct detection of the ∼ 8.4 eV internal conversion energy of 229mTh embedded in a superconducting nanowire"

Data for "Direct detection of the ∼ 8.4 eV internal conversion energy of 229mTh embedded in a superconducting nanowire"

Data presented is part of the journal manuscript "Optically Distributing Remote Two-node Microwave Entanglement using Doubly Parametric Quantum Transducers." Data includes graphical plots generated from numerical models and computations for various network topologies which illustrate their thresholds for achieving quantum information transfer.

Although Rydberg atom-based electric field sensing provides key advantages over traditional antenna-based detection, it remains limited by the need for a local oscillator (LO) for low-field and phase resolved detection. In this work, we demonstrate the general applicability of closed-loop quantum interferometric schemes for Rydberg field sensing, which eliminate the need for an LO. We reveal that the quantum-interferometrically defined phase and frequency of our scheme provides an internal reference that enables LO-free full 360 degree-resolved phase sensitivity. This internal reference can further be used analogously to a traditional LO for atom-based down-mixing to an intermediate frequency for lock-in-based phase detection, which we demonstrate by demodulating a four phase-state signal broadcast on the atoms.

Supplementary data for the article "Quantum state tracking and control of a single molecular ion in a thermal environment" by Yu Liu, Julian Schmidt, Zhimin Liu, David R. Leibrandt, Dietrich Leibfried, Chin-wen Chou, submitted to Science in 2024. The manuscript describes a quantum state-specific investigation of the molecular state evolution of a single CaH+ ion in a thermal environment. The molecular state can be tracked in real time with single quantum-state resolution and the thermal radiation-induced transitions can be reversed with coherent molecular state manipulation according to the outcomes of state measurements. Results on the transition rates are used to infer the properties of the thermal environment. The data may be used to reproduce the plots shown in the figures.

Rydberg atom-based receivers of modulated radio frequency (RF) fields are promising systems for measurements. These systems are self-calibrating, widely tunable, nearly transparent to RF fields, and can be electrically small. However, the instantaneous bandwidth of current Rydberg atom receivers is typically less than 1 MHz. Using two-photon electromagnetically induced transparency (EIT) to observe the 56D5/2 Rydberg state in cesium, we measure modulation sidebands on each tooth in a probe optical frequency comb that spans the D2 F=4-F'=5 transition resulting from transmission modulation of the probe beam. This transmission modulation occurs from changes in susceptibility of the room temperature cesium vapor as two RF fields impinge on the atoms. A strong RF local oscillator is resonant with the 56D-57P state and mixes with a weak RF signal field detuned from the RF LO by an intermediate frequency. Using a self-heterodyned electro-optic comb setup, we separate positive and negative sideband amplitudes and compare to an equivalent comb-free system. These data report EIT measurement with the comb system, local spectra around two comb teeth - one within and one outside the EIT line, and normalized minimum detectable RF signal field as a function of RF intermediate frequency used to evaluate the instantaneous bandwidth of the single frequency, positive sideband, and negative sideband datasets.

These data will appear in [1]. The abstract for that paper is given below:This paper presents a new multi-impedance-state line (MISL) in situ scattering parameter (S-parameter) calibration technique using on-chip superconducting transmission lines at 4 K that enables cryogenic calibration in a fixed signal path without the need for cryogenic switches or a cryogenic probe station. The method uses coplanar waveguide (CPW) models based on various impedance states of niobium (Nb), which has zero dc resistance below 9 K and a monotonically increasing resistance from 10 K to room temperature. The different impedance states are accessed by heating the 4 K stage of a cryostat and injecting up to 245 mA of current into the line. Using these states, we solve for the unknowns in an 8-term error model through a least-squares analysis. We first validate the MISL calibration technique by comparing it with short-open-load-reciprocal (SOLR) calibrated measurements in a cryogenic probe station, finding transmission agreement within 0.2 dB and uncertainty overlap for nearly all frequencies up to 26.5 GHz. We then apply the method to calibrate Nb CPWs with and without embedded Josephson junctions (JJs), using a fixed wire bonded connection, and without the use of cryogenic switches or movable probes. Strong agreement with the CPW models is demonstrated, with uncertainty overlap and differences below 0.1 dB up to 4.6 GHz without JJs and up to 2.4 GHz with JJs; resonances cause interruptions beyond these frequencies.[1] Thomas, J. N., Hoffmann, J., Flowers-Jacobs, N. E., Fox, A. E., Jungwirth, N. R., Johnson-Wilke, R. L., Dresselhaus, P. D., & Benz, S. P., "Cryogenic On-chip In Situ S-parameter Calibration Using Superconducting Coplanar Waveguides" submitted to the IEEE Transactions on Microwave Theory and Techniques Journal which if accepted will be published and available on IEEE website at a later date.